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vertex_array_helper.cc
vertex_array_helper.cc 5.92 KiB
//------------------------------------------------------------------------------
// This file is part of the OpenStructure project <www.openstructure.org>
//
// Copyright (C) 2008-2011 by the OpenStructure authors
//
// This library is free software; you can redistribute it and/or modify it under
// the terms of the GNU Lesser General Public License as published by the Free
// Software Foundation; either version 3.0 of the License, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
// FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
// details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with this library; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
//------------------------------------------------------------------------------
/*
Author: Ansgar Philippsen
*/
#include "vertex_array_helper.hh"
namespace ost { namespace gfx { namespace detail {
// TODO: refactor creation to geom, keep static list here
PrebuildSphereEntry& GetPrebuildSphere(unsigned int level)
{
static std::vector<PrebuildSphereEntry> prebuild_list(VA_SPHERE_MAX_DETAIL+1);
if(prebuild_list[level].vlist.empty()) {
unsigned int step1 = level*4;
unsigned int step2 = level*2;
float fact1 = M_PI*2.0/static_cast<float>(step1);
float fact2 = M_PI/static_cast<float>(step2);
// generate points on the sphere
std::vector<geom::Vec3>& vlist=prebuild_list[level].vlist;
vlist.push_back(geom::Vec3(0.0,1.0,0.0));
for(unsigned int i=0;i<step1;++i) {
for(unsigned int k=1;k<step2;++k) {
float ii = M_PI+fact1*static_cast<float>(i);
float kk = fact2*static_cast<float>(k);
vlist.push_back(geom::Vec3(sin(kk)*cos(ii), cos(kk), sin(kk)*sin(ii)));
}
}
vlist.push_back(geom::Vec3(0.0,-1.0,0.0));
// now the triangle indices for the above vertices
std::vector<unsigned int>& ilist=prebuild_list[level].ilist;
unsigned int point_count=vlist.size();
// top
unsigned int j=1;
for(unsigned int i=0;i<step1;++i) {
unsigned int k=i+1;
k%=step1;
ilist.push_back(0);
ilist.push_back(k*(step2-1)+j);
ilist.push_back(i*(step2-1)+j);
}
// bottom
j=step2-1;
for(unsigned int i=0;i<step1;++i) {
unsigned int k=i+1;
k%=step1;
ilist.push_back(point_count-1);
ilist.push_back(i*(step2-1)+j); ilist.push_back(k*(step2-1)+j);
}
// middle
for(unsigned int i=0;i<step1;++i) {
unsigned int k=i+1;
k%=step1;
for(unsigned j=1;j<step2-1;++j) {
unsigned l=j+1;
l%=(step2);
// add 2 triangles, counterclockwise
unsigned int p1=i*(step2-1)+j;
unsigned int p2=i*(step2-1)+l;
unsigned int p3=k*(step2-1)+j;
unsigned int p4=k*(step2-1)+l;
ilist.push_back(p1);
ilist.push_back(p3);
ilist.push_back(p2);
ilist.push_back(p2);
ilist.push_back(p3);
ilist.push_back(p4);
}
}
}
return prebuild_list[level];
}
std::vector<geom::Vec3> GetPrebuildCyl(unsigned int level)
{
static std::vector<std::vector<geom::Vec3> > prebuild_list(VA_CYL_MAX_DETAIL+1);
if(prebuild_list[level].empty()) {
unsigned int divs = (level+1)*4;
float step = 2.0*M_PI/static_cast<float>(divs);
std::vector<geom::Vec3>& vlist=prebuild_list[level];
for(unsigned int i=0;i<divs;++i) {
float angle=step*static_cast<float>(i);
vlist.push_back(geom::Vec3(std::cos(angle),std::sin(angle),0.0));
}
}
return prebuild_list[level];
}
void ico_sphere_subdivide(std::vector<geom::Vec3>& vlist,
const geom::Vec3& v1, const geom::Vec3& v2, const geom::Vec3& v3,
unsigned int l)
{
if(l==0) {
vlist.push_back(v1);
vlist.push_back(v2);
vlist.push_back(v3);
} else {
geom::Vec3 v12=geom::Normalize(0.5*(v1+v2));
geom::Vec3 v23=geom::Normalize(0.5*(v2+v3));
geom::Vec3 v31=geom::Normalize(0.5*(v3+v1));
ico_sphere_subdivide(vlist,v1,v12,v31,l-1);
ico_sphere_subdivide(vlist,v2,v23,v12,l-1);
ico_sphere_subdivide(vlist,v3,v31,v23,l-1);
ico_sphere_subdivide(vlist,v12,v23,v31,l-1);
}
}
std::vector<geom::Vec3> GetPrebuildIcoSphere(unsigned int level)
{
static std::vector<std::vector<geom::Vec3> > prebuild_list(VA_ICO_SPHERE_MAX_DETAIL+1);
if(prebuild_list[level].empty()) {
static float X = .525731112119133606;
static float Z = .850650808352039932;
static float vdata[12][3] = {
{-X, 0.0, Z}, {X, 0.0, Z}, {-X, 0.0, -Z}, {X, 0.0, -Z},
{0.0, Z, X}, {0.0, Z, -X}, {0.0, -Z, X}, {0.0, -Z, -X},
{Z, X, 0.0}, {-Z, X, 0.0}, {Z, -X, 0.0}, {-Z, -X, 0.0}
};
static unsigned int tindices[20][3] = {
{0,4,1}, {0,9,4}, {9,5,4}, {4,5,8}, {4,8,1},
{8,10,1}, {8,3,10}, {5,3,8}, {5,2,3}, {2,7,3},
{7,10,3}, {7,6,10}, {7,11,6}, {11,0,6}, {0,1,6},
{6,1,10}, {9,0,11}, {9,11,2}, {9,2,5}, {7,2,11} };
std::vector<geom::Vec3>& tmp_list=prebuild_list[level];
for (int i=0; i<20; ++i) {
geom::Vec3 v1(vdata[tindices[i][0]][0],
vdata[tindices[i][0]][1],
vdata[tindices[i][0]][2]);
geom::Vec3 v2(vdata[tindices[i][1]][0],
vdata[tindices[i][1]][1],
vdata[tindices[i][1]][2]);
geom::Vec3 v3(vdata[tindices[i][2]][0],
vdata[tindices[i][2]][1],
vdata[tindices[i][2]][2]);
ico_sphere_subdivide(tmp_list,
Normalize(v1),Normalize(v3),Normalize(v2),
level);
}
}
return prebuild_list[level];
}
} // detail ns
}} // ns